<template>
  <canvas
    v-if="canvasId"
    class="ec-canvas"
    :id="canvasId"
    :canvasId="canvasId"
    @touchstart="touchStart"
    @touchmove="touchMove"
    @touchend="touchEnd"
    @error="error"
  ></canvas>
</template>

<script>
import WxCanvas from "./wx-canvas";

function wrapTouch(e) {
  for (let i = 0; i < e.mp.touches.length; i += 1) {
    const touch = e.mp.touches[i];
    touch.offsetX = touch.x;
    touch.offsetY = touch.y;
  }
  return e;
}

export default {
  props: {
    onInit: {
      required: true,
      type: Function,
      default: null
    },
    canvasId: {
      type: String,
      default: "ec-canvas"
    },
    lazyLoad: {
      type: Boolean,
      default: false
    },
    disableTouch: {
      type: Boolean,
      default: false
    },
    throttleTouch: {
      type: Boolean,
      default: false
    }
  },
  // #ifdef H5
  mounted() {
    if (!this.lazyLoad) this.init();
  },
  // #endif
  // #ifndef H5
  onReady() {
    if (!this.lazyLoad) this.init();
  },
  // #endif
  methods: {
    init(callback) {
      if (!this.onInit) {
        console.warn("请传入 onInit 函数进行初始化");
        return;
      }

      const { canvasId } = this;
      this.ctx = wx.createCanvasContext(canvasId, this);

      const canvas = new WxCanvas(this.ctx, canvasId);

      const query = wx.createSelectorQuery().in(this);
      query
        .select(`#${canvasId}`)
        .boundingClientRect(res => {
          if (!res) {
            setTimeout(() => this.init(), 50);
            return;
          }

          const { width, height } = res;

          if (typeof callback === "function") {
            this.chart = callback(canvas, width, height);
          } else if (typeof this.onInit === "function") {
            this.chart = this.onInit(canvas, width, height);
          } else {
            this.chart = this.$emit("init", { canvas, width, height });
          }

          if (!this.chart) {
            return;
          }

          const { handler } = this.chart.getZr();

          this.handler = handler;
          this.processGesture = handler.proxy.processGesture || (() => {});
        })
        .exec();
    },
    canvasToTempFilePath(opt) {
      const { canvasId } = this;
      this.ctx.draw(true, () => {
        wx.canvasToTempFilePath({
          canvasId,
          ...opt
        });
      });
    },
    touchStart(e) {
      const { disableTouch, chart } = this;
      if (disableTouch || !chart || !e.mp.touches.length) return;
      const touch = e.mp.touches[0];
      chart._zr.handler.dispatch("mousedown", {
        zrX: touch.x,
        zrY: touch.y
      });
      chart._zr.handler.dispatch("mousemove", {
        zrX: touch.x,
        zrY: touch.y
      });
      this.processGesture(wrapTouch(e), "start");
    },
    touchMove(e) {
      const { disableTouch, throttleTouch, chart, lastMoveTime } = this;
      if (disableTouch || !chart || !e.mp.touches.length) return;

      if (throttleTouch) {
        const currMoveTime = Date.now();
        if (currMoveTime - lastMoveTime < 240) return;
        this.lastMoveTime = currMoveTime;
      }

      const touch = e.mp.touches[0];
      chart._zr.handler.dispatch("mousemove", {
        zrX: touch.x,
        zrY: touch.y
      });
      this.processGesture(wrapTouch(e), "change");
    },
    touchEnd(e) {
      const { disableTouch, chart } = this;
      if (disableTouch || !chart) return;
      const touch = e.mp.changedTouches ? e.mp.changedTouches[0] : {};
      chart._zr.handler.dispatch("mouseup", {
        zrX: touch.x,
        zrY: touch.y
      });
      chart._zr.handler.dispatch("click", {
        zrX: touch.x,
        zrY: touch.y
      });
      this.processGesture(wrapTouch(e), "end");
    }
  }
};
</script>

<style scoped>
.ec-canvas {
  width: 100%;
  height: 100%;
  flex: 1;
}
</style>
